Beam Manipulation by Hybrid Plasmonic-Dielectric Metasurfaces

A hybrid plasmonic-dielectric metasurface is proposed in order to manipulate beam propagation in desired manners. The metasurface is composed of patterned hybrid graphene-silicon nano-disks deposited on a low-index substrate, namely silica. It is shown that the proposed hybrid metasurface simultaneously benefits from the advantages of graphene-based metasurfaces and dielectric ones. Specially, we show that the proposed hybrid metasurface not only provides reconfigurability, just like previously proposed graphene-based metasurfaces, but also similar to dielectric metasurfaces, is of low loss and CMOS-compatible. Such exceptional features give the metasurface exceptional potentials to realize high efficient optical components. To demonstrate the latter point, focusing and anomalous reflection are performed making use of the proposed hybrid structure as examples of two well-known optical functionalities. This work opens up a new route in realization of reconfigurable meta-devices with widely real-world applications which cannot be achieved with their passive counterparts.

     

Melatonin,a toll-like receptor inhibitor: Current status and future perspectives

Toll-like receptors (TLRs) are crucial activators of inflammatory responses, they are considered immune receptors. TLRs are of fundamental importance in the pathophysiology of disorders related to inflammation including neurodegenerative diseases and cancer. Melatonin is a beneficial agent in the treatment of inflammatory and immune disorders. Melatonin is potent anti-inflammatory hormone that regulates various molecular pathways. Withal, limited studies have evaluated the inhibitory role of melatonin on TLRs. This review summarizes the current knowledge related to the effects of melatonin on TLRs in some common inflammatory and immunity disorders.     

Targeting HAUSP in both p53 wildtype and p53-mutant tumors

Inhibition of Mdm2 function is a validated approach to restore p53 activity for cancer therapy; nevertheless, inhibitors of Mdm2 such as Nutlin-3 have certain limitations, suggesting that additional targets in this pathway need to be further elucidated. Our finding that the Herpesvirus-Associated Ubiquitin-Specific Protease (HAUSP, also called USP7) interacts with the p53/Mdm2 protein complex, was one of the first examples that deubiquitinases (DUBs) exhibit a specific role in regulating protein stability. Here, we show that inhibitors of HAUSP and Nutlin-3 can synergistically activate p53 function and induce p53-dependent apoptosis in human cancer cells. Notably, HAUSP can also target the N-Myc oncoprotein in a p53-independent manner. Moreover, newly synthesized HAUSP inhibitors are more potent than the commercially available inhibitors to suppress N-Myc activities in p53 mutant cells for growth suppression. Taken together, our study demonstrates the utility of HAUSP inhibitors to target cancers in both a p53-depdentent and -independent manner.     

Quinolinic Acid Amyloid-like Fibrillar Assemblies Seed α-Synuclein Aggregation

Quinolinic acid (QA), a downstream neurometabolite in the kynurenine pathway, the biosynthetic pathway of tryptophan, is associated with neurodegenerative diseases pathology. Mutations in genes encoding kynurenine pathway enzymes, which control the level of QA production, are linked with elevated risk of developing Parkinson's disease. Recent findings have revealed the accumulation and deposition of QA in post-mortem samples, as well as in cellular models of Alzheimer's disease and related disorders. Furthermore, intrastriatal inoculation of mice with QA results in increased levels of phosphorylated α-synuclein and neurodegenerative pathological and behavioral characteristics. However, the cellular and molecular mechanisms underlying the involvement of QA accumulation in protein aggregation and neurodegeneration remain elusive. We recently established that self-assembled ordered structures are formed by various metabolites and hypothesized that these “metabolite amyloids” may seed amyloidogenic proteins. Here we demonstrate the formation of QA amyloid-like fibrillar assemblies and seeding of α-synuclein aggregation by these nanostructures both in vitro and in cell culture. Notably, α-synuclein aggregation kinetics was accelerated by an order of magnitude. Additional amyloid-like properties of QA assemblies were demonstrated using thioflavin T assay, powder X-ray diffraction and cell apoptosis analysis. Moreover, fluorescently labeled QA assemblies were internalized by neuronal cells and co-localized with α-synuclein aggregates. In addition, we observed cell-to-cell propagation of fluorescently labeled QA assemblies in a co-culture of treated and untreated cells. Our findings suggest that excess QA levels, due to mutations in the kynurenine pathway, for example, may lead to the formation of metabolite assemblies that seed α-synuclein aggregation, resulting in neuronal toxicity and induction of Parkinson's disease.     

Review of the genus Laelaspisella Marais & Loots,with the description of a new species from Iran (Acari,Laelapidae)

A new species of mite is described from Iran, Laelaspisella elsae sp. n. (Acari: Laelapidae). The new species was collected from bark of elm trees in Isfahan province. A revised diagnosis for Laelaspisella, as well as a key to the world species of the genus, are presented. Two species groups of Laelaspisella are proposed: those with seta pd3 on genu I and those without pd3 on genu I. Pseudoparasitus (Gymnolaelaps) tonsilis Karg, 1989a is transferred to Laelaspisella, based on its hypertrichous holodorsal shield, metasternal setae st4 absent and genu IV with ten setae. The problems with Laelaspisella canestrinii are explained and Laelaspisella canestrinii sensu Berlese (1903), (1904) and Costa (1962) is provided with a new name, Laelaspisella berlesei Joharchi, nom. n.